This invention relates to thermosetting emulsion latex mixture and particularly to acrylamide modified acrylic latices prepared from non-hydroxy-bearing vinyl unsaturated hydrocarbons and to clear and pigmented coatings prepared therefrom.
Thermoset clear and pigmented coatings and copolymer coatings bearing hydroxyl, carboxyl or amide functionality and capable of curing by aminoplast i.e. melamine-formaldehyde or glycoluril, cross-linking agents are known to the coatings art. Glycoluril compositions are known for use in solvent based coating compositions such as disclosed in U.S. Pat. No. 4,064,191 and for use in powder coatings such as disclosed in U.S. Pat. No. 4,118,437 and U.S. Pat. No. 4,255,558.
U.S. Pat. No. 4,442,257 (Borovicka et al) teaches low temperature thermosetting emulsion latex mixtures and to polymers containing both ethylene urea and hydroxyl (or hydroxyl plus carboxyl) functionality and which form a thermoset cross-linked polymer under moderate heating. U.S. Pat. No. 4,444,941 teaches low temperature cure coatings derived from acrylamide emulsion polymer containing both carboxyl and hydroxyl groups and which can cross-link with a glycoluril curing agent.
U.S. Pat. No. 4,255,558 (Turpin) teaches a self-curing powder paint composition comprising a thermoset glycoluril copolymer containing methylol or alkoxy methyl glycoluril groups adapted to cross-link with reactive hydroxyl, carboxyl or amide groups on the said copolymer.
It has now been found that an aqueous latex coating composition based on a thermosetting combination of glycoluril cross-linkers and certain reactive polymers, preferably an acrylamide polymer, but devoid of any hydroxyl units provides a low temperature cure surface coating.